Sassafras

Sassafras is the herb derived from the leaves of the North American sassafras tree, Sassafras albidum, in the laurel family (Lauraceae). Its signature aroma comes from safrole, a compound the US Food and Drug Administration banned as a food additive in 1960 after it was linked to liver cancer in animals. That ban falls on the parts where safrole concentrates: the root, the bark, and the oil pressed from them, the base of old-style root beer and sassafras tea.

The leaves are a different story. Carrying only trace safrole, they are recognized as safe and legal, which is why ground sassafras leaves, sold as filé powder, remain a common Creole and Cajun seasoning. The other legal route is safrole-free sassafras extract that has been distilled to strip the compound, used today to flavor root beer.